Functional group
acid
alcohol
aldehyde
alkanes
alkene
alkyl bromide
alkyl chloride
alkyl iodide
alkyne
amine
aromatic compound
aryl chloride
carbonitrile
cyclic hydrocarbon
ester
ether
halogen derivative
heterocyclic compound
hypervalent S
ketone
nitro compound
other
phenol or hydroxyhetarene
thiol

Number
73
38
20
28
35
17
31
9
6
44
170
20
12
8
8
42
22
48
5
25
17
29
33
5

Significance
0.02
2e-09
0.6
0.0001
3e-16
3e-07
7e-09
0.0001
0.0008
0.0002
1e-10
1e-08
2e-05
0.06
1
3e-09
0.07
1e-10
0.1
0.8
0.0002
0.09
6e-08
0.0002

t-value
2.47
-7.81
0.53
-4.43
-14.67
-8.33
-7.96
-7.10
-7.17
-4.01
-6.86
-9.58
-7.11
-2.26
-0.04
-7.58
-1.91
-8.28
2.09
-0.25
-4.91
-1.74
-7.00
-12.40

Mean error
-0.34
1.29
-0.07
0.31
1.07
1.50
1.09
0.86
0.49
0.55
0.55
1.04
1.63
0.21
0.02
1.01
0.73
1.02
-1.50
0.05
1.13
0.55
1.16
0.89

30

Dispersive component (kcal/mol)

Dispersive component (kcal/mol)

TABLE 5: Statistics from applying Student’s t test to the difference between the calculated and experimental means by funcational group.
Shown are the number of compounds in each functional group, the calculated t value, the computed significance (probability that t could be
this large or larger by chance) and the mean error for this group (in kcal/mol).

25

20

15

10

5

0

0

100

200

300

400
 

500

600

0

-5

-10

-15

-20

-25

3

0

100

200

300

400
 

Volume (A )

500

600

3

Volume (A )

(a) Repulsive part of nonpolar component versus volume

(b) Attractive part of nonpolar component versus volume

Figure 1. Repulsive and attractive parts of the nonpolar component versus volume. Shown are the repulsive (a) and attractive (b) parts
of the nonpolar component, as calculated using the WCA separation, plotted versus the solvent accessible volume for solutes in the test set.
Similar plots comparing the repulsive and attractive components to surface area are given in the main text.

27


